


Kinktober Day 7: Tentacles

by tiamatv



Series: Promptober 2020 [6]
Category: Supernatural
Genre: (Because Even In This Universe They're Definitely Switches), (More Cephaloporn Than Tentacle Sex), Alternate Universe - Fantasy, Anal Sex, Cecaelias, Comeplay, Crack Treated Seriously, Fluff and Smut, Loving Marriage, M/M, Oral Sex, Porn with Feelings, Prince Dean Winchester, Size Kink, Tentacle Sex, Top Castiel/Bottom Dean Winchester, Top/Bottom Versatile Castiel/Dean Winchester, octo!cas
Language: English
Status: Completed
Published: 2020-10-07
Updated: 2020-10-07
Packaged: 2021-03-08 04:54:02
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 9,523
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26889946
Author URL: https://archiveofourown.org/users/tiamatv/pseuds/tiamatv
Summary: “Dammit, Cas, stop it!” Dean complains, laughing. “Okay, seriously, how would the kingdom of Lebanon react if it knew their beloved Prince Castiel has a thing for feet?”Cas gives him a very wry look down the bridge of his nose, and gestures at the swirl of the eight octopus arms moving in the water underneath him. “I’m pretty sure the kingdom, if it were aware, would be much more offput by other things than my enjoying your toes, Dean.”(Now with art!)
Relationships: Castiel/Dean Winchester
Series: Promptober 2020 [6]
Series URL: https://archiveofourown.org/series/1954990
Comments: 35
Kudos: 197
Collections: The Destiel Fan Survey Favs Collection





	Kinktober Day 7: Tentacles

**Author's Note:**

  * For [Ltleflrt](https://archiveofourown.org/users/Ltleflrt/gifts).



> Updated: now with absolutely adorable art embedded at the end by [saltyravenclaw](http://www.archiveofourown.org/users/saltyravenclaw/pseuds/saltyravenclaw)! Please go take a look!
> 
> THIS has officially hit the "most kinky thing I've ever written" bar. Unbetaed, but you know, I'm weirdly proud of this one? I had so much fun writing it, and definitely think I AM going to clean it up eventually.
> 
> That said, there's a lot of random plot-like things thrown into here. Please don't expect any real plot. Just roll with it. Also: if you're sensitive to switching and mentions of switching? They're switches. Yep.
> 
> [Ltleflrt](https://archiveofourown.org/users/Ltleflrt/pseuds/Ltleflrt), you remember your cecaelia prompt? It's a bit different than you intended, I think, but this kind of happened...

Dean pulls his feet away from the edge of the water and tucks his legs under him. “Dammit, Cas!” he complains, laughing. “Stop tickling my damned toes.”

Dean’s husband—goddess love them, his _husband_ ; Dean’s the fucking luckiest asshole to ever live—gives him his most innocent look. “I can’t help it.”

To be fair, Cas is pretty good at that, with the big blue eyes and the way he can make his upper lip go so soft, but Dean’s not a sucker.

(There’s a really terrible pun in there somewhere, considering, well, Cas.)

But Dean’s too busy batting away the clever little pointed tip of a soft navy-blue octopus arm that’s poking out of the water and wiggling up onto the rock ledge Dean’s sitting on, aiming towards his… yup. His feet again.

“Hey, stop!” He flicks it with a finger just before it makes it to his instep, the little suckers a cheerfully pastel blue, shiny and dripping seawater onto the smooth, obsidian-dark rocks. It curls away from him, then tries again. “Okay, seriously, how would the kingdom of Lebanon react if it knew their beloved Prince Castiel has a thing for feet?” he demands, laughing.

The arm gives up and slips backwards into the water again with an annoyed little splash. Cas, sighing, reaches out and pulls the wider curve of it towards himself, and it merges back with the slow undulation of the rest.

Dean’s not entirely sure just _how_ sentient and independent Cas’s octopus arms are, or if Cas is just being a devious shit when they start getting handsy with Dean (hah hah) and Cas looks all innocent and indignant at them.

“I’m pretty sure the kingdom, if it were aware, would be much more offput by other things than my enjoying your toes, Dean,” Cas answers dryly, because mischievous or devious or whatever he is, he’s still a sassy creature. Then, like Dean could possibly miss what he’s got below the waist, he gestures downwards into the water with both hands.

In anyone else, that would have looked like him gesturing to his crotch. With the nearly black sand underneath him, though, the thin lines of his color play—that’s what he calls the narrow, color-changing stripes that run along the back of his octopus arms—catch the overhead sun in tiny little silver sparks like sequins along his lower body. With them contrasting gently like that, Dean can just catch the outline of the thick, gently waving giant octopus arms underneath him, the star-shaped mantle where they merge with Cas’s upper half like a skirt spread wide to keep him afloat.

Okay, so Cas might have a point about the good people of Lebanon not giving a shit about his foot fetish, if they knew.

Dean snickers and uncurls his legs again, letting one of his legs dangle back into the water to the knees and flipping a bit of seaweed in Cas’s direction. “I dunno, _I_ think you’re cute,” he announces.

It’s even true.

One of Cas’s arms—it might be the same one, but Dean can’t tell them apart even on a good day, much less when they’re moving like this—edges close again. Dean wiggles his toes at it and the arm darts away quickly enough that Cas mutters, “Ooof.” Okay, probably not the same one, then. But then Cas is swimming a little closer and smirking up at him, his eyes bluer and darker than the sunshine sky on the horizon.

Ocean eyes, that’s what his husband’s got. Storm eyes.

An arm starts creeping closer again, from the side this time, and Cas’s color play is tinged orange. Curiosity, Dean thinks. Or mischief. Probably both.

As an ordinary two-legger human, dry and wearing too-big clothes because Cas _hates_ the feel of cloth pressed tightly to his skin, Castiel of the Angelic Sea is good-looking. But in the sun of the private royal cove that Sam gifted to them for their marriage, shoulders back, surrounded by the dark sand under the water and the flash and flicker of his octopus arms, Dean’s husband is just plain fuckin’ gorgeous—wet and happy and kind of an asshole.

Dean laughs. “What _is_ it with you and my feet? You’ve got your own!” Most of the time, anyway. Cas does a better job of playing at being human these days than he had six months ago, when Dean had first bumped (literally) into him sitting naked on a promontory and staring out into a calm sea, like he was waiting for a tidal wave to come and drag him out and drown him.

(He had been.)

Dean shakes the thought away.

“Your feet are so much more interesting,” Cas answers, promptly. “It’s not as enjoyable to play with my own. My beans don’t wriggle as compellingly.” Two of his octopus arms coil to either side of his human biceps, like a shrug, before sinking back under the water. “It’s like the difference between the eel swimming in front of you and the one peeking out from under the coral. The other is more fun even when I’m not hungry.”

“Oh, yeah? What’s the eel think of that?” Dean asks, his tongue firmly in his cheek.

Cas opens his eyes innocently wide, and pushes himself a little higher, until his chest rises over the little lapping waves.

“I’d think that would depend if I’m hungry or not,” he answers, immediately.

Oh, Cas. Damnations, Dean loves him.

Cas nudges himself a little higher with a visible push of muscle, his abs clenching up temptingly, then leans all the way back in the water with a soft splash that seems to displace a lot less water than it should. He comes up gleaming, fuckin’ gorgeous, water slicking his hair, running down his neck and leaving his blue eyes even bluer. (He doesn’t have gills. The conversation that he and Dean had about how he breathes underwater left Dean more confused than not, but Sam seemed to get it.)

He’s showing off. Dean grins at him. “Yeah, yeah, you’re pretty,” he announces, rolling his eyes, and Cas beams, his narrow stripes flashing bright gold through the water, like Dean’s told him he’s the most damned wonderful being the goddess ever created.

(He’s pretty sure Cas knows Dean thinks it anyway.)

“You should go swim, though, before it starts getting too late,” Dean warns, waving a hand towards the stretch of the cove where it leads out into the ocean. Cas smiles brightly at him and rolls over, dropping under the surface. Dean can see the pale outline of his human upper body silhouetted against the soft, dark volcanic sand for just a couple of heartbeats before he shoots off and away—a lot faster than Dean would’ve thought anyone could swim with, well, definitely _not_ fins.

It wasn’t too long ago that Dean watched Cas disappear under the water, and he thought he’d never see him again. He still gets that feeling, sometimes, that twist of panic when the water closes over Cas’s dark hair and he disappears so fast it was like he was never there, not even leaving a ripple in the surface over him.

Not this time, though. Never again.

“ _I heard you, and it sounded like prayer,_ ” he said, once. “ _I had to come.”_

Dean believes it, now.

Dean pulls himself off the rock ledge and trots back to the sand, makes himself a little nest to lie down in before throwing down a blanket so he doesn’t end up with any under his balls (again). He was planning to do sentry rotations while Cas swam—just ‘cause Dean’s not crown prince anymore doesn’t mean he gets out from helping; he’s got to train the scout troops tomorrow, too. But he dozes in the late afternoon sun, instead, and wakes up warm, to the sound of a grumble and a couple of splashing flutters, a loud ‘splat’ of something wet hitting rock.

Cas is pulling himself out of the water by his human arms, anchored underneath him by two of the bigger, heavier octopus arms pressing against the edge. The rest of the arms are swirling and splashing in the water behind him to help leverage him onto the rock ledge where Dean likes to sit because it comes right up to the water, and it’s worn smooth by generations of people sitting on it and dangling their feet in. Getting from water and onto land is the only time Castiel’s not graceful in his normal form, but in the sunlight and out of the water, his lower half is more the color of sapphires than navy, his suction cups a creamy, delicate baby blue edged with lavender, his stripes almost silver. He wriggles further upwards.

Dean admires the sight groggily before he realizes and sits up. “You can stay in the water for a while longer, they’re not expecting us back until we gotta dress for dinner.”

Castiel doesn’t need any convincing. He immediately shoves backwards with a push of all of his arms, arcing joyfully in the air for just a moment before he hits the water with a splash—the most amazing fucking sight, all skin and long, lean, powerful limbs, creamy gold above the waist, gorgeous gemstone blue below it. He surfaces with just his eyes first, and Dean stretches towards the sky before going back to his rock ledge.

“I still don’t understand the point of that,” Cas grumbles, when he resurfaces the rest of the way, shaking water off his face. “Food is food no matter what you’re wearing to consume it. The fish don’t care if you’ve hung the prettiest coral from your neck?”

Dean doesn’t disagree with him. “The fact that we both think that is probably _why_ we’re both really bad at being princes, Cas,” he notes, but he gets onto his belly on his ledge, the wet stone smooth and slippery and getting him damp. He always comes back from the cove crusted all over with seawater and salt, but since Cas does, too, no-one’s stupid enough to ask any questions.

He doesn’t have to ask before Cas grabs the edge and pulls himself up just enough to drop a warmly tongued kiss on Dean’s lips, his mouth cool, tasting of salt, a little of fish. (He’s been snacking. Ellen’s gonna be upset when Cas doesn’t finish his dinner again.)

Cas is smiling when he pulls back—they both are. “I found you a present,” he says, proudly. One of his octopus arms rises from the water, the tip of it curled in a coil possessively around a small, twisty shell in… huh. It’s bright green, with delicate finer stripes of shimmer that look like the softer, gleaming pearly coating on the inside of an oyster shell. The arm drops the shell into Dean’s open hand, but takes a moment to brush its suckers over Dean’s fingers. Dean rubs a thumb over the colored stripe on the back of it—happy, bright yellow—as far as he can reach, and it squirms like a puppy’s tail before vanishing back into the water. “A turbo shell,” Cas announces.

Dean grins and turns it over in his fingers. He could probably ask Ellen to put a little hole in it, string it up with some of the other little things Cas finds him. “You’re doing this because of that blue feather I found for you when I was out riding last week, aren’t you.”

What, Cas can’t be the only one who brings him stuff.

“Feathers are _amazing_ ,” Cas tells him, solemn. “But they’re unnatural. This is much better.”

Dean gets a good belly-laugh out of that one.

He curls on his side on the rock and watches Cas swimming in contented circles for a little while before Cas’s head breaks the surface again. Cas is so serious—that’s sort of the way he’s built, and Dean hasn’t met enough cecaelia to know whether they’re all like that, or if it’s just Cas. (Dean might be biased because he’s never met another one who didn’t want him dead for ‘corrupting’ their prince, but that’s sort of a separate issue.)

But Cas always seems kind of stiff as a human—shoulders dipped in because keeping his spine straight and upright, fighting gravity by being vertical all the time, is still a little weird, to him, even after all these months. It makes him look smaller than he is—he’s not Sammy’s height in his human form, but no-one is—and kind of awkward. The only color he’s got is in those eyes of his.

Here, in the water? He’s fuckin’ beauty, grace and color. He’s _comfortable_.

But Cas can come out of the water to Dean. Dean can’t follow him in, not really.

“Hey, um, you know. Do you… do…” Dean licks his lips and pushes himself back into a sitting position, paddling a foot in the water to get Cas’s attention. He should ask, right? Yeah, he should ask. Cas surfaces the rest of the way, lifting himself out until his collarbones rise. “Do you miss it? The water?”

Castiel frowns and looks down at the shallow cove water surrounding him, visibly puzzled. His mantle spreads out like he’s testing the temperature, the soft webs between the arms puffing up and down. One of his sea-arms flicks out of the surface, curved like a question mark.

Dean snorts out a laugh. Still literal as ever. “No, you weirdo. You know, um. Your home.” He gestures out towards where the water hits the sky. “The ocean, the deep water.”

Cas doesn’t talk about it much. Dean doesn’t even know where it is, or how far, or in what direction. Cas’ll talk about coral, or barracudas, or getting chased by a clownfish away from its anemone. Now and again he mentions his sea cave, or a trench, or landmarks that Dean knows don’t exist above land. Dean doesn’t know if that’s because a lifetime of secrecy is just stamped into Cas’s being, or, well. Other reasons.

“Oh. Yes, of course I miss it,” Cas answers, matter-of-factly, and Dean’s heart stutters, dropping. “But I’m not… exiled anymore, I guess. I could go back. But I don’t _have_ to.”

He could. Cas could go back, but he doesn’t.

He doesn’t say, neither of them do, that Cas was originally exiled to land for helping Dean—saving Dean. Revealing himself to a human, when there aren’t many of his people left—most of the time, they’re mistaken for giant squid, or maybe little baby kraken, Dean would guess—was what got him kicked out of the cecaelia club.

Dean _didn’t_ know what Cas was, though, when Cas saved him—no, really, he was too sacked out by being conked on the head by Crowley, and dumped over the side of a boat, because no-one on the council really wanted Dean to be king, but Dad just wouldn’t let it go.

Dean didn’t even realize that he was being swum along on the surface, propelled by a set of muscley tentacles attached to a really smokin’ hot guy, until Cas deposited him on the ground—right here, right on this very cove.

(“Arms, Dean!” Cas complains, whenever Dean slips and he says the t-word. “I’m not a squid. I don’t call your legs ‘appendages!’”

Dean snorts. “Dude, you call my bellybutton a ‘crevice.’”)

It was just a pretense for Metatron to kick Cas out, sure. Just an excuse, ‘cause undersea politics are just as crappy as on land, it turns out. They both know that _now_ —but, well, it was all too fucking real for a while.

But Metatron is dead. Cas has his grace back, so he can walk on two legs whenever he wants (even if he is still sort of wobbly sometimes, especially in the middle of the night when he’s tired). Hannah, Castiel’s sister, is the one responsible for herding the octopus people now, which sounds even worse than herding cats.

That wasn’t anything Cas wanted to do in the first place, though. He just likes to observe, to study, to help. He doesn’t think he’s a leader, Dean gets that.

So it’s sort of fuckin’ hilarious that Cas ended up a prince-consort again _anyway,_ married to another prince who didn’t want anything to do with ruling.

In a way, it was easy. Dean always knew that Sam was gonna be better at the bureaucratic gladhanding bullcrap than Dean would _ever_ be. Everyone knew that. Dean was good with soldiers, with _normal people,_ not fuckin’ politicians. He’d tried to get himself kicked out of the running so many damned times! He and Sam had a _bet_ going on how long it’d take for Dean to cause a cross-border incident by using the wrong fucking spoon during a formal dinner or offering a mortal insult to someone by complimenting their hair.

But in the end? Dean insisting loud and clear on marrying his pretty guy—and not just a commoner, but a sea-carried _stranger_ found naked on the rocks and staring out over the ocean—had done it. If he wasn’t marrying Cas, he wasn’t marrying anyone. Period. Succession? Yeah, well. Too damned bad.

That had been John Winchester’s last straw.

They hadn’t known that getting married—willingly, whole-heartedly, so happy and so damned much in love—would break the hold Cas’s uncle had on his grace. They hadn’t known it would break the spell that kept Cas exiled, break the curse that’d held Cas trapped on two wobbly legs and far from the edge of the water.

So Dean had a couple of reasons that his wedding had been the best damned day of his life.

But the biggest reason is batting big blue eyes at him, dark hair plastered messily to his head, his wedding ring on a chain around his neck, octopus arms waving gently around him as he bobs in the water.

“You know what? Let’s go on a honeymoon,” Dean blurts.

Castiel blinks.

Dean yelps in surprise as the coil of an arm—it’s the sneaky one, he’d bet on it—winds around the foot he has in the water, the little press-pop of suckers against the bone of his ankle startling him.

It doesn’t feel bad or anything. Cas’s skin on his sea-arms, as he calls them, is like nothing Dean’s ever felt before, a bit crinkled and wrinkly when he has them tucked up against his body, tighter when he has them stretched out, but with firm, rigid muscle moving underneath, on the surface, they’re so _soft._ Dean might’ve spent a little while petting up and down one. Okay, more than a little while, because watching Cas go limp and dazed in the water just from Dean doing that, just pressing his hand up and down the thick stretch of them near his torso, kind of the same way he’d rub Cas’s thigh, and then tracing his fingers around the rims of the rubbery, bigger suckers, is awesome.

Dean lifts his foot out of the water and eyes the coil of arm that’s wrapped happily—happily?—around his ankle, when it comes up with him. Where they duck under Cas’s mantle, the arms are thicker than Dean’s biceps, each round cup as big around as Dean’s hand, but this one comes to a tip that’s not much bigger than Dean’s thumb. The little suction cup that’s stuck to his ankle bone now—Dean can feel _that_ —is the size of a coin. It twitches, tugging. He pokes the curl of it. “Are you tasting me?” he asks it.

What? If Cas claims they respond on their own, Dean can talk to the damned thing.

Cas snorts. “Dean.”

“What?”

Cas rolls his eyes and flicks water onto Dean’s legs. “Do I ask you if you taste with your fingers?”

“No,” Dean retorts. “But my fingers don’t move without my permission, either!”

Cas considers that, and finally dips a tiny, haughty nod. Dean drops his foot back into the water. The tip of the arm slides between his big toe and the one next to it, and Dean snorts, but at least it’s not actively tickling him again. “You were saying… a honeymoon?” Cas asks.

“Yeah!” Dean’s kind of getting into the idea now. “Oh, wait. You know what a honeymoon is, right?”

“Yes,” Cas answers, nodding. “Sam told me. It’s a time of a lot of sex after marriage.”

Oh, what Dean would’ve done to be there for _that_ talk. Sam’s the only one in the palace who knows what Cas really is—though everyone knows Cas is kind of odd. He’s so sweet that he’s gotten to be beloved as hell throughout Lebanon, though.

(They probably wouldn’t think it was as sweet if they knew that part of Cas’s helpfulness and solicitousness is because his people consider humans fatty and fragile and so terrifyingly easy to accidentally drown.)

Dean laughs. “I mean… I guess. Kind of. It’s a vacation, you go away for it.”

Cas’s blink is so fucking guileless Dean _knows_ he’s in for it. The smile flirts around his blue eyes before it makes it to his lips. “We already mate a lot, though,” Dean’s husband observes, very seriously. “We don’t need to leave to do that.”

Dean refuses to admit that he finds Cas still calling it ‘mating’ so freaking cute. He just… he refuses. “Yeah, I mean… well, yeah.”

Dean’s not sorry about it, not even remotely. Teaching a guy who’s never had a cock and balls and ass and _prostate_ before just how _awesome_ it can all feel? Fuck, every day’s like Dean’s birthday, sometimes. The first couple of times, Cas _had_ to be on his back ‘cause he couldn’t keep control of his legs when Dean had a mouth or a hand around him. He came _twice_ the first time he had his legs thrown over Dean’s shoulders and Dean’s cock in him, because guess what? He’s really, _really_ flexible. Dean didn’t even care that Cas’s heels left bruises on his back and he almost crushed Dean’s ears with his knees.

“But I was thinking… we could take a boat out? A live-aboard boat—for me, anyway. A month or so on the ocean. Just us.” Dean gestures into the water and kicks his foot back and forth. The suckers around his ankle hang on. He grins down at it—damned thing—before he looks up at his husband; Cas is smiling right back at him. “You know, so you can stay like this if you want, the whole time. Dive down and hang out with your family, if we get to the right waters.”

“You’re my mate. My husband. You’re my family,” Cas answers, and it’s immediate. Dean’s heart does a slow, rolling twist, graceful like Cas is in the water. One of his other sea-arms pats Dean’s calf. Yeah, Cas is feeling handsy. Dean drops his other foot into the water and a sucker presses to his shin, like a kiss. They both smile as the rest of the arm coils around and around, bumping upwards to rest a loop on Dean’s knee. “And I don’t think Hannah likes you.”

“You did kind of give up an army of underwater octopus people rather than _kill_ _me_ according to _your laws_ , Cas,” Dean agrees, wryly. He reaches a hand down to pet the curve of muscle that’s nuzzling his kneecap.

“I gave up a battery of cecaelia that I didn’t want, rather than kill you,” Cas corrects—okay, that sounds _exactly the same_ to Dean, “and I always thought it was an incredibly stupid law.” He tugs on Dean’s legs. “Come into the water with me.”

Dean looks up into the sky, considering. They’ve been away awhile, and _technically_ he and Cas are supposed to actually make it to that formal dinner tonight. Queen Charlie’s supposed to be arriving from Mondoor this evening and she hasn’t met Cas yet…

But they’ve been married just a few months. They’re practically still newlyweds. A grand total of _no-one_ wonders where they are when they disappear together, and sure as hell everyone knows to knock. (They’ve all learned better. Since Cas’s people don’t do privacy, Cas doesn’t care if everyone knows they’re having sex, or even if anyone sees his naked ass pounding the hell out of Dean.) Everyone thinks the two of them come out to their private cove to canoodle under the sky anyway, which is why no-one’s gonna bother them even if they’re late…

Yeah, Dean’s already shucking his shirt and his breeches as he’s thinking about all that. By the time he considers that Sammy’s going to roll his eyes _so hard_ again, he’s already tossing himself in. He hits the still water of the cove with a massive splash that’s _nothing_ like how Cas glides in feet-first even when he’s in human form, and barely seems to cause a ripple.

Cas is against him, around him, almost before the water closes over Dean’s head. He seems so much _bigger_ in the water, his sea-arms longer than his torso, and so damned thick. One of them coils around Dean’s torso, and Dean grabs onto it, letting Cas pull them together. A sucker plasters accidentally—he _thinks_ —onto one of his nipples, and Dean yelps.

Cas chuckles, “Oh. Sorry.” The arm wraps more politely around Dean’s waist.

Dean grumbles, and pinches the edge of a sucker. From Castiel’s “ _Mmm_ ,” he doesn’t think that’s a real effective deterrent, though.

They sink a little, but Dean’s head stays over the water, Cas’s chin dipping just under the surface as they rearrange. Cas’s human arms tuck around Dean’s back, and he grabs onto Dean’s ass, pulling him against his muscled, naked torso.

Dean laughs and hangs on, legs around Cas’s waist, arms on his shoulders. The water carries them, bobbing, and under him he can feel the slow undulating wave of Cas’s mantle keeping them both afloat and pushing them back a little higher. Cas’s skin is cool against his, but warmer than the water around them. The coils of two arms brush the backs of Dean’s thighs, then settle there, one winding all the way around his leg, helping hold him up, sure and muscular, but… huh.

Dean shivers.

Huh.

Cas looks down, interested, his face momentarily disappearing underwater before it reappears, dripping. “We can’t mate underwater, can we,” he says, a little wistfully. “At least, not without a spell.”

Yeah, okay, Cas isn’t exactly one to just pretend that the half-chub Dean’s got going on now doesn’t exist. What the hell can Dean say, anyway? His so body’s used to Cas, now—the way he always smells like ocean and wind, the feel of their chests pressing together, bare and wet, Cas’s waist between Dean’s knees. Dean blushes first—dammit, Cas—

Then he blinks.

Yeah, they’ve got magic-users on land, too—potioners, hedge-witches, even a few real mages, like Charlie—but some of the things that Dean saw when they were going after Metatron had been _fucking unreal._ “Wait. There are _spells_ for that?” he demands.

“Probably, but I’m sure they’re forbidden,” Cas sighs. Well… yeah, probably. “You would look so amazing with sea-arms.” He runs a hand down Dean’s flank, skipping over his ribs, cradling the rise of Dean’s ass. He looks dreamy, like he’s imagining it. “I would love to see your mating colors.”

“Thanks, I guess,” Dean answers, his tongue lodged firmly in his cheek.

Then Dean actually _thinks_ about this.

Wait, what the fuck. He and Cas screw like _bunnies._ In every conceivable position. Cas in him, him in Cas, mouths and hands and every damned thing either of them can think of, ‘cause Cas hasn’t got _any_ hangups whatsoever about who’s on top, bottom, or sideways, or what’s supposed to go where.

So how the hell hasn’t Dean thought about this before?!

“Wait, but… you, uh… how… you don’t… have a cock, right?” Dean peers down into the water between them, then realizes just how stupid that is. First of all, it’s not like Dean would be able to see anything: Cas is dark blue under the waist, and the way his sea-arms move make it kind of difficult to see anything else for the sinuous patterns his color play lines make in the water. Secondly, he _knows_ that Cas doesn’t have a cock, ‘cause Dean didn’t know whether to laugh, cry, or fall to his knees and praise the goddess when Cas was so amazed about the idea of an organ that existed basically _just_ for sex.

(Well, not exactly, but in Cas’s mind, close enough. He’s pretty casual about peeing.)

“Oh. I have a cotylus.” One of Cas’s arms rises from the water beside them. The tip waggles at Dean, like it’s waving. Dean blinks at it and suppresses the urge to wave back.

It takes Dean way, way, _way_ too long to realize exactly what Cas is saying and how that connects to the long blue arm with its sky-colored suckers that’s currently poking out from the warm, clear water, next to Cas’s shoulder.

“Wait. What? But… that’s… that’s your _arm_ ,” Dean blurts.

“Yes, one of them, and it’s my cotylus,” Cas repeats, patiently. The arm flops behind his back and into the water like it’s embarrassed, with a loud splash that gets Cas’s whole neck wet. A moment later, a thick blue curl of muscle rolls up against Cas’s shoulder. Cas sighs and pats it, soothingly. “It hardly matters, Dean. I’m used to being a two-legger. And I very much enjoy mating with you like that.” He catches himself, and smiles, sweetly. “Sex. It’s very nice.”

It is, it sure as fuck is, but… Dean hesitates.

He hesitates.

It’s crazy, what he’s thinking, right? It’s probably crazy?

But… hell, the path they took to get here is fucking crazy. Cas is his _husband_ , and sometimes Dean feels like all he does is take things away from Cas—take and take and take.

“Does it feel different? Than when we’re mati—” dammit, Cas has got him doing it now, too. He sees from the way Cas’s eyes squinch, little smile-lines appearing at the corners of them, that Cas caught it, dammit. “Fucking,” Dean finishes, firmly. Yeah, he’s red in the face, so what?

Castiel chuckles, softly. “I don’t know?” he admits. The tip of one of his sea-arms flicks upwards, and Dean doesn’t move as it comes tentatively towards his face. Cas’s eyes are soft and drowning when he finally touches. It’s a caress, those little suckers making tiny kisses across Dean’s cheeks, the freckles that Dean knows are probably darker now because he was napping in the afternoon sun. “I never took a mate before you.” He smiles, ruefully. “My own people thought me very strange, Dean. ‘Cracked like an oyster among otters,’ was the expression, I think.”

What? What the hell?

Well, that clinches it. Cas must feel Dean’s knees tighten against his waist, because the sea-arm flips off his face and around his shoulders to help brace him, and his human arms tighten around Dean like he thinks Dean’s hanging on ‘cause he thinks he’s going to fall. That’s not exactly it.

“So let’s try it,” Dean says.

Yeah, he said it.

Cas blinks. “What?”

“Your, uh… your… cotylus? It goes… in, right?” Goddess help him, Dean’s a fully grown adult who, as Cas pointed out, has a lot of sex; he can make these words happen.

“Yes, when used as a mating organ it penetrates and deposits semen, but…” Cas licks his lips, and he’s _never_ been able to hide his interest—never could, it was why no-one except Dean’s dad was all that _surprised_ by what ended up happening—but he still says, carefully, “Dean, I already love you however you are, and however you will have me. You do not have to feel like you have to—”

Dean’s smallclothes might be cold and wet, but the cock he presses against Cas’s stomach through them, definitely more than half-hard, now, is hot, and an answer. “Lemme see it,” Dean says, and he can feel the familiar catch of it in his throat: it’s a low purr of a demand.

For sure this is weird. But Dean doesn’t care. Fuck it—this is Cas, it’s all still _his_ Cas, octopus arms and weird sense of humor and all, and Dean’s never _not_ found him sexy as all hell.

Cas is looking shy and flushed when he brings one of his sea-arms up again, and the tip flicks out of the water like a warning before it ducks back under, and Dean feels it brush against his wrist. Without hesitation, he closes his palm around it. Under the water, he can see that Cas’s color stripes are bright pink, and they’re starting to… _glow_?

Huh. That’s new.

“Mating colors,” Cas answers Dean’s curious look, and his cheeks are pink, too.

It feel… well, it just feels like the end of one of Cas’s sea-arms. Normal, as far as Dean can tell. Delicate skin on the top, a little wrinkly, but soft; little round cups of suckers on the bottom, moving shyly against Dean’s fingers. It feels good in his hand, familiar, and the idea of having it pushing _in_ him, this intimate part of Cas… it ain’t half bad. _He_ can’t tell the difference from any of Cas’s other octopus arms, but if Cas says this is what it’s for, it’s what it’s for. He tugs on it, playfully, pressing a thumb to the center of one of the little suckers.

Cas sucks in a sharp breath.

Oh, that’s also new.

“How much of it’s supposed to go in?” Dean asks, interested now. There’s a tight ball of _something_ in his stomach, but he can’t tell if it’s nerves or curiosity. It’s not disgust, though.

Cas doesn’t pull his cotylus arm out from where Dean’s playing with it—he raises another one, though, and studies it, then measures it out between his hands. “About… to here, I think. It has a mating ridge; this one doesn’t.”

Dean gulps. O _kay,_ so… in his two-legger form, Cas has got a big cock with a fucking _amazing_ shape, just the slightest hint of an upcurve that hits just right in some positions, and Dean can take him in pretty easily by now with good prep. But that… what Cas is measuring out is a good two, maybe three inches longer, and ends up thicker than Dean’s wrist.

But Cas glares at the graceful blue octopus arm wobbling question marks in front of him, and then pushes it back underwater with a firm movement of his human hand. “And stop bothering Dean’s feet, now is not the time to tickle him,” he mutters.

Dean’s bark of laughter makes some of the tension and nervousness in his stomach evaporate a little. Well, that answers Dean’s question about whether it’s a specific arm that’s got a thing for his toes.

Okay, that’s… well, the tips of Cas’s sea-arms are pretty narrow. So it’ll definitely start out easy, that’s not the problem. If they work up to it, there’s a good taper, so it’ll just be a matter of some stretching… and Dean likes that, doesn’t he? Hell, he likes it even more than Cas, who’s normally pretty simple to get off. It might even feel amazing.

He runs his fingers between the suckers of the cotylus he’s holding, again, and his thumb comes away wet and warm from the tip. And it stays wet, almost oily. Which should be an incredibly stupid thing to say considering that his hand is _underwater,_ but trust Dean, of all people, to know the difference?

“Did it… was it…?” Dean frowns, and gently tugs the arm upwards and the tip out of the water. It _is_ firmer than it was, and a little thicker, though not quite rigid or anything. And it’s covered with thick, glistening stuff that’s not seawater; even as Dean watches, a droplet of it beads up at the tip, a delicate, pearly, milky white, and trickles downwards.

Cas likes to poke and prod at him with the tips of his arms, he does it all the time when they’re in the water, and Dean’s pretty sure they’ve never done _that_ before.

Dean rubs the stuff between his fingertips. “Wow,” he notes, as his fingers glide smooth against each other. “You’ve been holding out on me, sweetheart, this’s better than the lube we buy.” A lot better, the rub of it almost silky.

“I’m aroused,” Cas says, simply.

Okay, _fuck_ , Cas is the only damned being who can ramp Dean up with a perfectly factual statement of his condition.

Then again, it’s Cas’s eyes that go wide when Dean, carefully, licks the fluid off the tip of his sea-arm.

Huh. It’s… sweet? What? _No_ , that can’t be right… Dean’s brain is maybe just getting confused by the salt water and the fresh tang of Cas’s skin.

Cas shudders when Dean closes his lips over the very tip and suckles, and gets another burst of something in a pulse against his tongue. The fluid is thick, and it really _is_ sweet, and tastes… kind of good mixed with the salt. Surprisingly, yeah. Not like fruits or candy, but… sweet. Huh.

When Dean pulls off the tip and starts putting kisses on the small, twitching suckers on its underside, all of Cas’s other arms jerk in the water, one of them wrapping hard around Dean’s calf like it’s trying to drag him closer to Cas. When Dean finds the mating ridge a few inches down—it’s exactly what it sounded like, a flexible, muscular ridge underneath that soft, soft skin—and nibbles curiously at it, very gentle with his teeth, Cas _moans_.

Yeah, this isn’t going to be difficult at all.

When Dean lets go, grinning triumphantly, Cas wraps himself around Dean—an embrace with both his human arms, all eight sea arms twisting around Dean’s body as they sink, heavy, the curves of them at Dean’s back, his shoulders, his legs. It feels _good_ being squished in him like this—Cas is warmer than he normally is, which Dean guesses is because he’s turned on—and in the water, the long pink stripes running down each arm are glowing so brightly they’re tinging the water pink around them, casting warm purple shadows on Cas’s blue skin.

Dean’s momentarily afraid Cas is going to forget Dean can’t breathe underwater, but he doesn’t; he swims them both back up to the surface after a few heartbeats of making like a limpet—heh heh.

Dean’s not-even-remotely-human husband isn’t even trying for human behavior anymore, though.

Dean thought he might mind that. But it’s still _his_ Cas making hungry, happy, low sounds. His hands are gripping at Dean, running up and down his torso, grabbing hold of Dean’s hair at the back of his head in a yank that just about crosses Dean’s eyes. His sea-arms, though, they’re the ones that strip off Dean’s smallclothes and fling them off into the water—distantly Dean realizes they might have to retrieve those later… or, well, or not, won’t be the first pair of underwear that they’ve ruined or lost.

The thick web of Cas’s mantle is fluttering hard to keep them afloat, because the gentle waving motions of his sea-arms that normally balance it are gone. One of the arms is around Dean’s right knee. Another is pressing sucking kisses along Dean’s left thigh. Another’s at the small of Dean’s back, but it’s starting to pat down the line of Dean’s ass… it doesn’t try to press into him, though.

Instead, it slips between his legs and starts stroking that stretch of skin between his balls and his hole, and oh _fuck_ it feels for all the world like a gentle, tickling tongue.

Dean’s eyes _cross_ when a set of little suckers make it onto his cock along with all of this, and he feels the hot blurt of precome into the water between them. He doesn’t know if Cas can feel it or smell it or what—he knows Cas has water senses that he doesn’t—but Cas sure as hell can, because he growls, “Yes, yes, _Dean_.” His voice is already always deep, always just that little gravel edge away from _human,_ but this is the sound of an earthquake.

Dean’s just holding on to Cas’s shoulders for dear life by now, so along for the ride right now that if Cas _wanted_ to drag them off to sea so they could fuck in water so deep Dean can’t see the bottom, much less swim it, he’d have said “oh, fuck, _oh yes_.”

He says it aloud when the delicate tip of an arm—he can’t keep track of them anymore, goddess fuck him, they’re _everywhere_ —slides between his cheeks, the bigger suckers of two others being used to hold him wide, wide open; Dean’s gonna have bruises on his ass he’ll feel for a week. From the way it slips and slides against his hole, getting him all nice and wet and ready, Dean knows _exactly_ which of Cas’s sea-arms it is.

(Distantly, he thinks, huh—yeah, whatever personal lube Cas is making? Definitely keeps working even in water. Pretty fucking amazing.)

“Yeah, yeah,” Dean pants, burying his face in Cas’s neck, inhaling him, breathing in _this_ —getting to fuck _his_ husband in every possible way. “C’mon, Cas, _get in me_.”

Cas pulls him out of the line of his neck by his hair, and Dean snarls, but it’s only so Cas can kiss him. Cas’s tongue is making small curls in Dean’s mouth—and oh, goddess bless them all, Cas is such a fucking _good_ kisser—when the tip stops teasing and slides into Dean’s ass.

It doesn’t hurt at all—he didn’t think it would, since Dean’s virginity is more extinct than dinosaurs, and Cas’s human cock is _not_ small. It kind of… _wriggles_ in, though, rolling and tugging against Dean’s rim. Which feels weird, but it’s interesting, and Dean breathes out a little ‘huh’ against Cas’s lips.

The noise he makes is impatient when Cas starts to work just that tiny little bit in and out of him in small thrusts—c’mon, Cas knows he can take more than that, easy; hell, Dean’s probably still a little open and wet from earlier this afternoon. Getting fucked this way feels almost like the tip of a finger, to be honest. A finger that moves around inside him—Dean’s getting to like that more and more, though, the more Cas does it, that so-soft skin feeling delicate against Dean’s rim as it twists—

Dean doesn’t quite feel the cotylus spilling more of that lubricating stuff into him, but he definitely feels the difference in the slip and slide of it. Cas smiles, and growls something—it’s not in Common, so it’s his own language.

But Dean doesn’t have the chance to ask what he’s saying as more of Cas’s cotylus arm pushes into him. It turns into a slow, good stretch—not even achy, it’s so slow and ever so gradual, and there’s no sense of sudden _give_. Just a little that turns into a little more and then _more_ , and Dean realizes he can feel the edge of a sucker wriggling when Cas works in just a little _more_ —

A sucker—a big one, he realizes, presses against him inside. The arm _curves_.

“ _Fuck!_ ” Dean swears, his back arching.

He really thought, hey, it’ll probably feel just like Cas’s cock. A little bigger, shaped a bit different.

It doesn’t feel a single damned thing like Cas’s cock.

Cas’s cock doesn’t _move_ like that inside him—less thrusting than pressing and curving and _goddess fucking bless_ twisting inside him in fantastic, bizarre little rolls. Cas is biting his lower lip hard, staring straight into Dean’s face, but Dean’s not even sure he’s seeing the world around them, much less Dean, he’s concentrating so hard.

“You’re so warm inside,” he mumbles. “Dean—there’s more—”

Oh, _yeah._ “Give it to me, Cas,” he gasps, and spreads his legs wider, toes curling in the water as Cas gives him more. Fuck, he’s really feeling that stretch now. “How do I get you off?”

Cas’s laugh is a thunderstorm. “Oh… oh, beloved, that will not be a problem. Are you—”

“I’m good,” Dean assures him, and then gasps, because that better be Cas’s mating ridge that he felt popping into him, because he’s never been so fucking full in all his life. “ _Goddess—"_

“Yes,” Cas moans, squeezing his eyes shut. His lips are parted; he’s panting. He looks wrecked. He looks like it feels _so_ good for him, and the triumph that Dean feels is joyful, obscene.

When Cas opens his eyes again, Dean stares.

Humans’ pupils get big, when they’re really fucking into their business. Dean knows this. He’s seen it in the mirror—he’s seen it on others’ faces. He’s seen it on _Cas’s._

Cas’s pupils aren’t doing that this time. Instead, his irises are _glowing,_ even brighter than the pink streaks running down his arms _._ They’re the electric blue of one of Charlie’s experiments.

Okay, that’s _really_ fucking hot.

“I’m going to swim us to the rocks, Dean,” Cas says, halting, his words stumbling like he’s having a hard time remembering how to speak another language. “I would like you to grab hold.”

Dean could really do with Cas _not_ moving and squirming the sea-arm up Dean’s ass while he’s giving him directions, but he manages a “What, _now_?”

“Yes, _now_ ,” and Cas suits action to word, the water rushing past them almost before Dean has time to take a deep breath and hold it, closing his eyes as the spray splatters them both before they duck under the surface.

He really has no idea what Cas is up to, he’s focused too hard on what’s going on _inside_ him, the way his balls are drawn up tight and his cock practically tries to wiggle itself every time one of Cas’s suckers pulses delicately against his prostate. So when Cas says, “Hold, Dean,” and puts his hands on the familiar ledge of rock, he does, because the thought of doing anything that Cas tells him to seems pretty good right now.

It's amazing. It’s fucking amazing. Dean’s crammed full, there are sea-arms bracing his legs, cool stone under his fingers, and Dean _almost_ thinks he’s managed to get a handle on what’s going on—

Hands—hands?—grip his hips. Something warm and wet and soft and _familiar_ engulfs his cock, and Dean’s eyes fly open.

He’s looking at the dark volcanic sand, the stone, the pile of damp clothes he left scattered on the sand. He’s looking at their horses tethered in the distance. He’s _not_ looking at Cas, because—

He looks down.

Through the water, Cas’s blue eyes peek at him. Dean would be able to tell he’s smiling just from the way his mouth is tightening around Dean’s cock.

The cotylus pushes in his hole, rippling in the most unbelievably delicious wave, and _thrusts_.

Dean comes harder than he ever has in his life, with Cas’s mouth moving hot and expert around his cock, and one of Cas’s sea-arms stuffed up his ass. The only thing that keeps him from slamming his hips forward is the knowledge that he’ll shove Cas against the rock outcropping behind him, and instead Dean drives his hips back against—

_Fuck!_

He and Cas moan together as Dean’s ass flexes and quivers around the fucking _thick_ thing wedged inside him. Since Cas is moaning around Dean’s _cock_ , though, the vibration is too much, the press of Cas’s tongue along his underside and the quiver of his throat sends another, almost painful run of sweet spasms ricocheting down Dean’s back, and Dean never wants him to stop doing it, _never_.

Cas surges upwards a few heartbeats later, when Dean’s still deciding if he’s remembered how to breathe—with the cotylus still moving in rocking, rolling thrusts in his ass, the answer might still be ‘no’—and sticks his tongue down Dean’s throat. Dean’s own come is bitter and salty on Cas’s tongue, but Cas seems to like the taste, always has—licks it off Dean’s thighs, his stomach.

“Cas?” he asks, shaky. “What—”

“I’m so close, Dean, I’m so…” Cas babbles, curved around Dean so tightly Dean’s face is wedged under the curve of Cas’s jaw. Cas’s other sea-arms are twisting so hard in the water that it’s churning around them. One wraps around Dean’s knee and pulls him open, roughly, and Dean didn’t _think_ it was possible for him to get hard again, but his body gives it a pretty good try anyway. His cock presses, happy, to where Cas would have a bellybutton, if he’d been human. “May I? May I, please?”

Holy fuck, Cas begging and clutching and writhing like that is so hot that Dean’s pretty sure he’d agree to _anything._

“Yeah, yeah, give it to me, sweetheart,” Dean croons, and bites Cas’s neck—hard.

He doesn’t know if it’s a cecaelia thing or a Cas thing, but Cas fucking _loves_ being bitten. His neck, his shoulder. Teeth scraping the back of his ear makes his knees go wobbly. Someday, Dean wants to find out if he can get Cas to come just by nibbling on the insides of his thighs.

So he’s not surprised that Cas wails, “ _Dean!_ ” in his ear and goes rigid against him.

He _is_ surprised at the sudden full _bulge_ he feels at his ass, where Cas is still wedged inside him. Dean yelps as he feels it shove into him, holy fuck that’s _big_ , that’s even bigger than the portion of the arm that’s inside him, what the—the stretch is so intense it’s shocking, like four fingers, like a _fist_. If Dean hadn’t been so turned on, loose and relaxed from a completely epic orgasm, it might have hurt—but as it is, with his body still balanced on the edge of wantwantwant, it’s fucking amazing. It rolls roughshod over where Dean’s prostate is still swollen and Dean _feels_ another spurt of come get milked right out of him just from the pressure, clouding up the water between them—

Cas sobs, and all of a sudden that huge pressure is gone because— _oh._

 _Holy. Fuck_.

The sudden rush of wet inside him is _hot_ , deliciously hot, filling up Dean to leaking as Cas fucking _deposits_ his semen into his ass, coming in a single huge spurt that Dean can practically feel in his throat.

One part of Dean’s brain registers, “Oh. Oh, that was what that bulge was.”

The rest of Dean is too caught in _oh, fuck_ and _oh, yes_ and feeling like he might be coming all over again without so much as a hand or a finger or a sucker on his cock, his hips jerking forward. Cas’s cotylus slips free from inside Dean’s ass in the gush of _wet_ filling him up inside, and Dean yowls, not sure he likes being empty again all of a sudden.

But then Cas is kissing him again, kissing him deep and sloppy, there are arms and tentacles tucked everywhere around him, and holding him tight.

Dean goes limp in his husband’s arms.

Dean’s not quite sure how he ends up back on the sitting rock—probably the same way he ended up on it the first time, nine months ago, brain completely rattled with concussion, eased up onto there because Cas is stronger than he looks. It’s not precisely comfortable—it’s _rock_ —but it’s not the worst.

Except this time? This time, he turns his head to the warmth besides him.

This time, Cas is lying on his side next to him, pretty much the most amazing creature Dean’s ever met, salt water making his hair an unruly seaweed mess.

Definitely not the worst.

Cas hasn’t changed back to human yet. Dean reaches out and runs a finger down the smooth curve where his waist turns into the ruffled skin of his mantle, like a skirt draped over the thick stalks of his octopus arms—lying still, now, like they’re exhausted, too. His color play stripe is a deeply contented royal purple.

One of the arms wriggles close to Dean’s foot. It wraps around his big toe. Dean doesn’t stop it—but when he meets Cas’s eyes, they both chuckle.

Dean lies the rest of the way back and pops his neck. His ass is sore, and stretched. He can _feel_ that thick, clinging wet still inside him.

It’s so, so good.

“Well. Okay. So, you liked that,” Dean mutters to the empty, darkening blue sky, maybe a cloud or two scudding across the horizon. Yep, they’re definitely not going to make it for dinner.

Cas grumpily mumbles something that is definitely not a language that Dean understands. Dean doesn’t speak one word of Cas’s language—his throat can’t actually make those sounds—but he’s pretty sure that it means “Look who’s talking.”

“We’re definitely going on a honeymoon, an’ if you want to go to the deep ocean? Fuck your family. We’ll go,” Dean decides, and Cas wriggles that fucking amazing half-octopus body closer. Dean turns his head to look at him. Cas is well within the range of what anyone would consider acceptable personal space—but Dean’s the one who closes the distance so their noses touch, and the color of Cas’s eyes—not glowing anymore—swallows him whole. “Are they really gonna be that pissed?”

“It won’t matter if they are.” Cas shrugs one shoulder. A coil of sea-arm loops over and tucks itself over Dean’s belly—tentatively, at first, then letting its solid weight down when Dean reaches down to stroke it. “All in all, we’re a little more stubborn than the mermaids. Independent. We prefer to each have our own territory, for the most part. I think it comes from our origin, since octopuses are solitary, and mostly cannibals,” Cas tells him, completely straight-faced. “If I don’t want them near my mate, they won’t dare.”

Huh. Okay, _that’s_ all a lot of new information—mermaids are out there? Holy crap, Sam’s gonna have kittens—but Dean’s not sure if he’s too fucked-out to care, or horrified or…

Wait. Did Cas say ‘ _cannibals_?’

Dean blinks, and his hand tightens on the firm muscle where one of Cas’s coils is draped over his waist. A sucker pulls at his belly button. Goddess love him, Cas’s sense of humor. “Okay, which part of that’s the joke?” Dean asks, blurry.

Cas blinks at him, slowly, then cocks his head to the side in silent incomprehension before just settling his cheek against Dean’s shoulder with a sigh. He turns laboriously on his side and one of his human arms joins the octopus arm draped over Dean.

Dean loves his husband. He really does, tentacles (okay, okay, sea arms) and all. Hell, he did even before he knew that Cas could fuck him stupid with one of them. And he really does want to learn more about the guy he’s gonna be spending the rest of his life with—glowing lines and prehensile suckers and octopus lube—what the hell—and everything messy and wonderful and crazy.

But goddess fuckin’ bless, Cas is weird sometimes.

“Next time,” Cas tells him, and he looks as drowsy and content as Dean’s feeling, lying out on the smooth rock next to him with suckers shifting against Dean’s thigh, a human arm draped over Dean’s waist, and the rest of his big octopus arms draped limp over the edge of the rock and the tips of them dangling in the water. “Maybe next time you could mate my siphon? I think that might feel very good.”

Dean blinks himself back awake. “Siphon?” he asks, sleepily.

He sort of registers one of Cas’s octopus arms wrapping one of Dean’s wrists and pulling it towards the core of Cas’s lower body, but he _definitely_ notices when it carries his hand under Cas’s mantle, and lets his fingertips come to rest against… huh. The mantle settles back down, warm and heavy over the back of Dean’s hand and forearm.

Dean’s definitely never explored under here, but damn, it’s like Cas doesn’t have any skin that isn’t so fucking perfectly soft _anywhere_. He runs his fingertips carefully over a web that seems smoother than the softer, wrinkly skin on the back of Cas’s sea arms, definitely thinner, slippery with seawater and pleasantly warm with the way Cas’s body heats up with exertion…

There’s a flexible ridge, but then the tips of Dean’s fingers dip into a soft, soft little hole.

Cas shivers. “Yes,” he murmurs.

It flexes around Dean’s fingertips like it’s trying to suck him in.

Oh.

Oh, wow.

Okay, yeah, Dean’s alright with a little weird.

~fin~

And now with lovely art by [saltyravenclaw!](http://www.archiveofourown.org/users/saltyravenclaw/pseuds/saltyravenclaw)

**Author's Note:**

> It was going to be rimming or tentacles. Why I chose tentacles? I have no idea. Well, I have some idea, I was reading about octopus mating. And the independent nerve systems in their arms. And their color changes. And... okay, yeah, I know just how it turned into tentacles.
> 
> How this turned into nearly 10K of happy fluff and cuddles and a wee bit of it's-octopus-arms-not-tentacles-dammit sex? That I have no idea about, what the heck.
> 
> Alright, friends, I think this is going to be the last Kinktober I write on a weekday. NONE of them are ending up being the cute little smut drabbles that I wanted them to be and I need to actually, you know... sleep.


End file.
